{"id":48785,"date":"2025-03-18T07:52:33","date_gmt":"2025-03-18T07:52:33","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=48785"},"modified":"2025-03-18T07:58:04","modified_gmt":"2025-03-18T07:58:04","slug":"terraform-tutorias-cli-environment-and-predefined-meta-variables-complete-reference","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/terraform-tutorias-cli-environment-and-predefined-meta-variables-complete-reference\/","title":{"rendered":"Terraform Tutorias: CLI environment and predefined\/meta variables Complete Reference"},"content":{"rendered":"\n

Terraform CLI environment variables reference<\/h2>\n\n\n\n
Environment Variable<\/strong><\/td>Description<\/strong><\/td>Example Usage<\/strong><\/td><\/tr>
TF_LOG<\/strong><\/td>Controls logging verbosity. Values: TRACE, DEBUG, INFO, WARN, ERROR, OFF.<\/td>export TF_LOG=DEBUG<\/td><\/tr>
TF_LOG_PATH<\/strong><\/td>Specifies log file path to store logs.<\/td>export TF_LOG_PATH=.\/terraform.log<\/td><\/tr>
TF_INPUT<\/strong><\/td>Determines if Terraform prompts for user input. Set to false to disable.<\/td>export TF_INPUT=false<\/td><\/tr>
TF_VAR_name<\/strong><\/td>Sets Terraform input variables from the environment. Example: TF_VAR_region.<\/td>export TF_VAR_region=us-west-1<\/td><\/tr>
TF_CLI_ARGS and TF_CLI_ARGS_name<\/strong><\/td>Defines default CLI arguments for Terraform commands. Example: TF_CLI_ARGS_plan.<\/td>export TF_CLI_ARGS=’-input=false’<\/td><\/tr>
TF_DATA_DIR<\/strong><\/td>Changes Terraform data directory from the default `.terraform`.<\/td>export TF_DATA_DIR=\/custom\/data\/dir<\/td><\/tr>
TF_WORKSPACE<\/strong><\/td>Specifies the workspace to use in Terraform.<\/td>export TF_WORKSPACE=production<\/td><\/tr>
TF_IN_AUTOMATION<\/strong><\/td>Indicates if Terraform is running in an automated environment (CI\/CD).<\/td>export TF_IN_AUTOMATION=true<\/td><\/tr>
TF_REGISTRY_DISCOVERY_RETRY<\/strong><\/td>Number of retries for Terraform Registry discovery.<\/td>export TF_REGISTRY_DISCOVERY_RETRY=5<\/td><\/tr>
TF_REGISTRY_CLIENT_TIMEOUT<\/strong><\/td>Sets timeout duration for Terraform Registry client operations.<\/td>export TF_REGISTRY_CLIENT_TIMEOUT=30<\/td><\/tr>
TF_STATE_PERSIST_INTERVAL<\/strong><\/td>Defines how frequently Terraform writes its state file.<\/td>export TF_STATE_PERSIST_INTERVAL=10<\/td><\/tr>
TF_CLI_CONFIG_FILE<\/strong><\/td>Specifies custom path for Terraform CLI configuration file.<\/td>export TF_CLI_CONFIG_FILE=$HOME\/.terraformrc<\/td><\/tr>
TF_PLUGIN_CACHE_DIR<\/strong><\/td>Specifies the directory for Terraform plugin cache.<\/td>export TF_PLUGIN_CACHE_DIR=$HOME\/.terraform.d\/plugin-cache<\/td><\/tr>
TF_IGNORE<\/strong><\/td>Defines patterns for files and directories that Terraform should ignore.<\/td>export TF_IGNORE=’*.bak’<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Terraform predefined and meta variables reference<\/h2>\n\n\n\n
Built-in Variable<\/th>Description<\/th><\/tr><\/thead><\/table><\/figure>\n\n\n\n
terraform.workspace<\/code><\/td>Returns the current workspace name<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
path.module<\/code><\/td>Returns the current module path<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
path.root<\/code><\/td>Returns the root module path<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
path.cwd<\/code><\/td>Returns the current working directory<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
count.index<\/code><\/td>Current index<\/strong> in a count<\/code> loop.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
each.key<\/code>, each.value<\/code><\/td>Current key-value<\/strong> in a for_each<\/code> loop.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
var.<variable_name><\/code><\/td>References an input variable<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
local.<local_variable><\/code><\/td>References a local variable<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
module.<module_name>.<output><\/code><\/td>Retrieves an output from a child module<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
self<\/code><\/td>Refers to current resource instance<\/strong>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
depends_on<\/code><\/td>Explicitly sets dependencies<\/strong> between resources.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
env.<ENV_VAR><\/code><\/td>Retrieves environment variables<\/strong> from the shell.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Comprehensive Guide: Terraform CLI Environment Variables & Predefined Variables<\/h1>\n\n\n\n

1. Terraform CLI Environment Variables Reference<\/h2>\n\n\n\n

Terraform allows configuring its behavior using various environment variables. These variables control logging, input handling, workspace management, and registry discovery settings. Below is a detailed guide with use cases and examples.<\/p>\n\n\n\n

1.1 Logging & Debugging<\/strong><\/h3>\n\n\n\n

TF_LOG<\/strong><\/h4>\n\n\n\n
    \n
  • Description:<\/strong> Controls Terraform logging verbosity.<\/li>\n\n\n\n
  • Possible Values:<\/strong> TRACE<\/code>, DEBUG<\/code>, INFO<\/code>, WARN<\/code>, ERROR<\/code>, OFF<\/code><\/li>\n\n\n\n
  • Use Case:<\/strong> Useful for debugging Terraform execution.<\/li>\n\n\n\n
  • Example:<\/strong> export TF_LOG=DEBUG terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n

    TF_LOG_PATH<\/strong><\/h4>\n\n\n\n
      \n
    • Description:<\/strong> Specifies a log file path to store logs.<\/li>\n\n\n\n
    • Use Case:<\/strong> Useful when debugging Terraform automation pipelines.<\/li>\n\n\n\n
    • Example:<\/strong> export TF_LOG_PATH=.\/terraform.log terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n
      \n\n\n\n

      1.2 Input Handling<\/strong><\/h3>\n\n\n\n

      TF_INPUT<\/strong><\/h4>\n\n\n\n
        \n
      • Description:<\/strong> Determines if Terraform prompts for user input. Set to false<\/code> to disable interactive prompts.<\/li>\n\n\n\n
      • Use Case:<\/strong> Useful in CI\/CD environments.<\/li>\n\n\n\n
      • Example:<\/strong> export TF_INPUT=false terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n

        1.3 Variable Handling<\/strong><\/h3>\n\n\n\n

        TF_VAR_name<\/strong><\/h4>\n\n\n\n
          \n
        • Description:<\/strong> Sets Terraform input variables from the environment.<\/li>\n\n\n\n
        • Use Case:<\/strong> Allows dynamic configuration of Terraform variables without modifying the .tf<\/code> file.<\/li>\n\n\n\n
        • Example:<\/strong> export TF_VAR_region=us-west-1 terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n

          TF_CLI_ARGS and TF_CLI_ARGS_name<\/strong><\/h4>\n\n\n\n
            \n
          • Description:<\/strong> Defines default CLI arguments for Terraform commands.<\/li>\n\n\n\n
          • Use Case:<\/strong> Ensures that Terraform always runs with specific flags.<\/li>\n\n\n\n
          • Example:<\/strong> export TF_CLI_ARGS='-input=false' terraform apply<\/code> export TF_CLI_ARGS_plan='-refresh=false' terraform plan<\/code><\/li>\n<\/ul>\n\n\n\n
            \n\n\n\n

            1.4 Terraform State & Data Management<\/strong><\/h3>\n\n\n\n

            TF_DATA_DIR<\/strong><\/h4>\n\n\n\n
              \n
            • Description:<\/strong> Changes Terraform data directory from the default .terraform<\/code>.<\/li>\n\n\n\n
            • Use Case:<\/strong> Useful when running multiple Terraform executions in parallel.<\/li>\n\n\n\n
            • Example:<\/strong> export TF_DATA_DIR=\/custom\/data\/dir terraform init<\/code><\/li>\n<\/ul>\n\n\n\n

              TF_WORKSPACE<\/strong><\/h4>\n\n\n\n
                \n
              • Description:<\/strong> Specifies the workspace to use in Terraform.<\/li>\n\n\n\n
              • Use Case:<\/strong> Automate Terraform workspace switching.<\/li>\n\n\n\n
              • Example:<\/strong> export TF_WORKSPACE=production terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n

                TF_IN_AUTOMATION<\/strong><\/h4>\n\n\n\n
                  \n
                • Description:<\/strong> Indicates if Terraform is running in an automated environment (CI\/CD).<\/li>\n\n\n\n
                • Use Case:<\/strong> Helps Terraform suppress interactive prompts.<\/li>\n\n\n\n
                • Example:<\/strong> export TF_IN_AUTOMATION=true terraform apply<\/code><\/li>\n<\/ul>\n\n\n\n
                  \n\n\n\n

                  1.5 Terraform Registry & Plugin Management<\/strong><\/h3>\n\n\n\n

                  TF_REGISTRY_DISCOVERY_RETRY<\/strong><\/h4>\n\n\n\n
                    \n
                  • Description:<\/strong> Number of retries for Terraform Registry discovery.<\/li>\n\n\n\n
                  • Use Case:<\/strong> Useful when working in unstable network environments.<\/li>\n\n\n\n
                  • Example:<\/strong> export TF_REGISTRY_DISCOVERY_RETRY=5<\/code><\/li>\n<\/ul>\n\n\n\n

                    TF_REGISTRY_CLIENT_TIMEOUT<\/strong><\/h4>\n\n\n\n
                      \n
                    • Description:<\/strong> Sets timeout duration for Terraform Registry client operations.<\/li>\n\n\n\n
                    • Use Case:<\/strong> Useful in slow networks.<\/li>\n\n\n\n
                    • Example:<\/strong> export TF_REGISTRY_CLIENT_TIMEOUT=30<\/code><\/li>\n<\/ul>\n\n\n\n

                      TF_PLUGIN_CACHE_DIR<\/strong><\/h4>\n\n\n\n
                        \n
                      • Description:<\/strong> Specifies the directory for Terraform plugin cache.<\/li>\n\n\n\n
                      • Use Case:<\/strong> Helps speed up Terraform runs by avoiding plugin downloads.<\/li>\n\n\n\n
                      • Example:<\/strong> export TF_PLUGIN_CACHE_DIR=$HOME\/.terraform.d\/plugin-cache<\/code><\/li>\n<\/ul>\n\n\n\n
                        \n\n\n\n

                        1.6 Miscellaneous Terraform Configurations<\/strong><\/h3>\n\n\n\n

                        TF_STATE_PERSIST_INTERVAL<\/strong><\/h4>\n\n\n\n
                          \n
                        • Description:<\/strong> Defines how frequently Terraform writes its state file.<\/li>\n\n\n\n
                        • Example:<\/strong> export TF_STATE_PERSIST_INTERVAL=10<\/code><\/li>\n<\/ul>\n\n\n\n

                          TF_CLI_CONFIG_FILE<\/strong><\/h4>\n\n\n\n
                            \n
                          • Description:<\/strong> Specifies a custom path for the Terraform CLI configuration file.<\/li>\n\n\n\n
                          • Example:<\/strong> export TF_CLI_CONFIG_FILE=$HOME\/.terraformrc<\/code><\/li>\n<\/ul>\n\n\n\n

                            TF_IGNORE<\/strong><\/h4>\n\n\n\n
                              \n
                            • Description:<\/strong> Defines patterns for files and directories that Terraform should ignore.<\/li>\n\n\n\n
                            • Example:<\/strong> export TF_IGNORE='*.bak'<\/code><\/li>\n<\/ul>\n\n\n\n
                              \n\n\n\n

                              2. Terraform Predefined and Meta Variables Reference<\/strong><\/h2>\n\n\n\n

                              Terraform provides a set of predefined variables<\/strong> that allow access to system metadata.<\/p>\n\n\n\n

                              Built-in Variable<\/th>Description<\/th><\/tr><\/thead>
                              terraform.workspace<\/code><\/td>Returns the current workspace name.<\/td><\/tr>
                              path.module<\/code><\/td>Returns the current module path.<\/td><\/tr>
                              path.root<\/code><\/td>Returns the root module path.<\/td><\/tr>
                              path.cwd<\/code><\/td>Returns the current working directory.<\/td><\/tr>
                              count.index<\/code><\/td>Current index in a count<\/code> loop.<\/td><\/tr>
                              each.key<\/code>, each.value<\/code><\/td>Current key-value in a for_each<\/code> loop.<\/td><\/tr>
                              var.<variable_name><\/code><\/td>References an input variable.<\/td><\/tr>
                              local.<local_variable><\/code><\/td>References a local variable.<\/td><\/tr>
                              module.<module_name>.<output><\/code><\/td>Retrieves an output from a child module.<\/td><\/tr>
                              self<\/code><\/td>Refers to the current resource instance.<\/td><\/tr>
                              depends_on<\/code><\/td>Explicitly sets dependencies between resources.<\/td><\/tr>
                              env.<ENV_VAR><\/code><\/td>Retrieves environment variables from the shell.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

                              Example Usage:<\/strong><\/p>\n\n\n

                              output \"workspace\"<\/span> {\n  value = terraform.workspace\n}\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n
                              output \"current_path\"<\/span> {\n  value = path.module\n}\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
                              By understanding and utilizing these Terraform environment variables and predefined expressions<\/strong>, users can optimize their infrastructure as code (IaC) workflows efficiently.<\/p>\n\n\n\n